package de.thedevstack.conversationsplus.xmpp.disco;

import android.util.Base64;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import de.thedevstack.conversationsplus.ConversationsPlusApplication;
import de.thedevstack.conversationsplus.crypto.axolotl.AxolotlService;
import de.thedevstack.conversationsplus.xmpp.Xep;
import de.thedevstack.conversationsplus.xmpp.chatstate.ChatState;
import de.tzur.conversations.Settings;

/**
 */
public final class FeatureRegistry {
    public static final String IDENTITY_TYPE = "phone";

    private static final String[] LEGACY_FEATURES = {
            "urn:xmpp:jingle:1",
            "urn:xmpp:jingle:apps:file-transfer:3",
            "urn:xmpp:jingle:transports:s5b:1",
            "urn:xmpp:jingle:transports:ibb:1",
            "http://jabber.org/protocol/muc",
            "jabber:x:conference",
            "http://jabber.org/protocol/caps",
            "http://jabber.org/protocol/disco#info",
            "urn:xmpp:avatar:metadata+notify",
            "http://jabber.org/protocol/nick+notify",
            ChatState.NAMESPACE,
            AxolotlService.PEP_DEVICE_LIST+"+notify"};
    private static final String[] LEGACY_MESSAGE_CONFIRMATION_FEATURES = {
            "urn:xmpp:receipts"
    };
    private final List<String> features = new ArrayList<>();
    private static final FeatureRegistry INSTANCE = new FeatureRegistry();

    public static void add(String featureNamespace) {
        if (null != featureNamespace) {
            INSTANCE.features.add(featureNamespace);
        }
    }

    public static void remove(String featureNamespace) {
        if (null != featureNamespace && INSTANCE.features.contains(featureNamespace)) {
            INSTANCE.features.remove(featureNamespace);
        }
    }
    public static void add(Xep xep) {
        add(xep.featureNamespace());
    }

    public static void remove(Xep xep) {
        remove(xep.featureNamespace());
    }

    public static List<String> getFeatures() {
        Collections.sort(INSTANCE.features);
        return INSTANCE.features;
    }

    public static String getCapHash() {
        StringBuilder s = new StringBuilder();
        s.append("client/" + IDENTITY_TYPE + "//" + ConversationsPlusApplication.getNameAndVersion() + "<");
        MessageDigest md;
        try {
            md = MessageDigest.getInstance("SHA-1");
        } catch (NoSuchAlgorithmException e) {
            return null;
        }

        for (String feature : getFeatures()) {
            s.append(feature + "<");
        }
        byte[] sha1 = md.digest(s.toString().getBytes());
        return new String(Base64.encode(sha1, Base64.DEFAULT));
    }

    private FeatureRegistry() {
        this.features.addAll(Arrays.asList(LEGACY_FEATURES));
        if (Settings.CONFIRM_MESSAGE_RECEIVED) {
            this.features.addAll(Arrays.asList(LEGACY_MESSAGE_CONFIRMATION_FEATURES));
        }
    }
}